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Hidden cloud layer revealed

By Andy Coghlan

A LAYER of high, invisible cirrus clouds has been overlooked by weather balloons. If the clouds, which trap the Earth’s radiation, are more abundant than previously thought, today’s models for predicting global warming could be inaccurate.

Clouds at altitudes of around 8 to 14 kilometres are invisible to the naked eye because they’re so thin and diffuse. Researchers knew they existed but didn’t realise that standard sensors on weather balloons weren’t picking them up, so they may have vastly underestimated the amount of cloud at those altitudes.